1. Field of the Invention
The invention concerns a turbocharger device for an internal combustion engine according to the pre-characterizing portion of claim 1.
2. Description of the Related Art
From DE 31 42 499 A1 a turbocharger device is known with two exhaust turbochargers of different size arranged sequentially, wherein one of the turbochargers can be engaged or disengaged via controllable valves. The control of the valves occurs electronically depending upon the respective operating condition of the internal combustion engine, whereby an optimal efficiency can be achieved.
A comparable turbocharger device is known from WO 91/18192, which likewise shows two sequentially arranged exhaust gas turbochargers, however in this case the turbines of both turbochargers can be bypassed by a waste gate with a closeable valve.
This type of turbocharger device conventionally requires a comparatively large installation space, which is often not available, particularly in small vehicles.
The invention is thus concerned with the task of providing a turbocharger device with compact construction.
This problem is inventively solved by a turbocharger device with the characteristics of patent claim 1.
In accordance with the inventive improvement, a common exhaust gas inflow channel is provided on the turbocharger housing, via which the exhaust gas of the internal combustion engine can be supplied to both turbines in the turbine housing. From the exhaust gas inflow channel, two channel segments branch out, via which the exhaust gas is supplied to each of the turbines respectively. Further, a regulator means is provided, which is situated in the branch point of the exhaust gas channel section of the exhaust gas supply channel. Using the controllable regulating means, the exhaust gas inflow to at least one of the turbines can be adjusted. The exhaust gas inflow channel, which integrates both channel segments branching out from the exhaust gas inflow channel, as well as the regulating device are integrated in the turbine housing, whereby on the one hand a particularly space-saving arrangement can be realized, and on the other hand, the device achieves a modular character, whereby it is possible to construct the inflow channel, the channel sections, and the regulator means as a single exchangeable unit.
The turbine housing, in which the inflow channel of the two channel segments and the regulating means is provided, can either be a part of only one exhaust gas turbocharger or however could be a part of a common housing for both exhaust gas turbochargers.
According to a preferred further developed embodiment it is envisioned that the turbine housing includes a mounting flange, via which the turbocharger device can be rigidly secured to the exhaust gas outlet of the internal combustion engine. The exhaust gas inflow channel in this embodiment is located in the area of the mounting flange. This embodiment offers the advantage that the entire turbocharger device can be secured to the internal combustion engine via the mounting flange, whereby the complexity of the mounting and dismounting of the device is reduced.
In a preferred further development, the two exhaust gas turbochargers of the device are of different size and designed for different volumetric throughputs, wherein the regulating means in the branch of the two channel segments, each segment respectively associated with one of the turbines, can be switched in such a manner that at small loads or, as the case may be, low engine speeds (RPM), the channel segment associated with the larger exhaust gas turbocharger is blocked, in comparison to which at high loads or, as the case may be, high RPM, this channel segment is opened. The two turbochargers are in this manner optimally matched to each other, in that at lower RPM the smaller turbocharger with lower inertia and lag and better responsiveness is driven, and at higher RPM in comparison the larger turbocharger preferably comes into employment, and provides a higher load capacity. Both chargers taken together, and matched to each other in this manner, make it possible to provide a high air throughput and an approximately constant torque.
Finally, it can be useful to integrate into an exchangeable module the two air supply channels, which are provided on the one hand between the compressor output of a first compressor and the compressor input of a second compressor, and on the other hand, on the compressor output of the second compressor. This module is advantageously constructed to be independent of the turbine housing, but, however, at the same time forms a part of the turbocharger device. The exchangeability of the module has the advantage, that the versatility of the device is increased in particular with respect to the adaptation or fitting to various size relationships. Further, the adaptability can be increased in the manner that the compressor output of the first compressor and the compressor input of the second compressor lie on parallel planes; hereby, a further simplification of the assembly and disassembly of the module on the turbocharger device is made possible.
It can be advantageous to provide a connecting channel between the two air supply channels, in which a bypass valve (butterfly valve) is provided. Using the connecting channel and the bypass valve a part of the fresh air flow can be directed to bypass the second compressor, whereby a further degree of freedom for the adjustability of the turbocharger device results, which is advantageous in particular for small volume (displacement) motors, for example for passenger carrying automobiles. The modular design of the air supply channels assembled into a single construction unit or component makes it possible to provide the module with and without connecting channel, or as the case may be, to provide suitable modules which can be exchanged with each other, or however to equip a module without connecting channel with such, or as the case may be, to remove the connecting channel from a module of this type. Modules without connecting channels are particularly employable in utility vehicles.